Variable speed drive



Dec. 19, 1961 L. DRAGONUK 3,013,438

VARIABLE SPEED DRIVE Filed Feb. 11,1959 7 Sheets-Sheet 2 Fig. 2

INVENTOR. LEO DRAGONUK A r TORNE Ys Dec. 19, 1961 ,L. DRAGONUK VARIABLE SPEED DRIVE 7 Sheets-Sheet 5 Filed Feb. 11, 1959 INVENTOR.

- LEO DRAGONUK A TTORNEYS Dec. 19, 1961 DRAGONUK VARIABLE SPEED DRIVE Filed Feb. 11. 1959 7 Sheets-Sheet 4 INVENTOR. LEO DRAGONUK ATTORNEYS Dec. 19, 1961 Filed Feb. 11, 1959 L. DRAGONUK VARIABLE SPEED DRIVE 7 Sheets-Sheet 5 A TTDRNE YS L. DRAGONUK VARIABLE SPEED DRIVE Dec. 19, 1961 7 Sheets-Sheet 6 Filed Feb. 11, 1959 000m 9% 02 om? 00m 00m wwwvw wm N9 ZN 3w mm mm 3 mm mm s .0 9 Ill o m 5 d I n mm J a: w 3 w 6 g m mm I] 2. om 2 mm x I 2 I mm mm 9 vm vm ow 00. W a

i we I M M mm mm w 2 mm mm Dec- 1 1961 DRAGONUK 3,013,438

VARIABLE SPEED DRIVE Filed Feb. 11, 1959 7 Sheets-Sheet 7 INVENTOR.

L E0 DRAGONUK ATTORNEYS 3,013,438 Patented Dec. l9, 1961 3,913,438 VARKABLE SPEED DREVE Leo Bragonnlr, 316i; Mayflower Road, Plymouth Meeting, Pa. Filed Feb. 11, 1959, Ser. No. 792,634 (Ilaims. (Cl. Nb-lid} (Granted under Title 35, US. Code (1952), see. 266) The invention herein'described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This invention relates to a variable speed drive and control means therefor, and more particularly relates to a transmission which is devoid of disengageable clutches efi'ective for shifting gears or otherwise changing the speed of the transmission.

Heretofore there has been a considerable problem involved in obtaining a slip-free and smooth variable speed drive transmission capable of providing a variable speed output from a constant speed input, a constant speed output from a variable speed input, and a variable speed transmission which can also be combined with a variable speed output.

More particularly, in connection with gun turrets, it is desirable to have a variable speed transmission capable of providing a variable speed output from a constant speed input and which is free of any clutches effective to disengage the drive during a change of speed between the input and output shafts. Should the gun turret of an aircraft be disconnected from its drive, it is free to be buffeted by the slipstream or other external forces with the result that the control and orientation thereof is disadvantageously and at least momentarily lost.

in connection with alternators, which are used to supply electricity for an aircraft and more particularly for an aircraft powered by a variable speed turbine or another type engine, a constant speed output to the alternator is desired although the input speed may be variable. The speed of a turbine may vary, for example, between three and ten thousand rpm. Since it is essential, for obvious reasons, to provide a constant speed drive to the alternator, it has generally been found unsatisfactory to provide a transmission which must be entirely disengaged from its drive, such as by means of a clutch, for purposes of changing the gear ratio. Therefore, there has been a need for a variable speed transmission which is devoid of any clutches but which transmission has ade quate speed range to permit the alternator to be driven at a constant speed although the aircraft engine may vary in speed over a considerable range.

Also, it is contemplated that the invention can be used in conjunction with a variable speed input for provlding'a variable speed output by means of the variable speed transmission.

The invention, which comprises a slip-free variable speed transmission free of any clutches and-having a suitable control therefor, is considered to be a solution to the problems of providing a variable speed output from a constant speed input, a constant speed output from a variable speed input, and a variable speed output from a means referred to is that the balancing metrically located in substantially the effected.

and is. capable of Still another object of the invention is the provision of a mechanical integrator which can be compactly constructed to transmit, without slip, unlimited power.

More particularly, it is an object'to provide a variable speed transmission which does not rely upon the use of a clutch which not only'may slip, but which even more disadvantageously may at least momentarily disconnect the input from the output, and thereby interrupt the drive.

Another object of the invention is the provision of a transmission, as set forth'in the claims, which the speed of the output thereof can be changed smoothly in either direction while the input continues to be driven in only one direction and, if desired, at a constant speed.

Still another object of the invention is to provide a coaxial variable speed transmission capable of varying the output of a constant speed input without interrupting or disconnecting the drive.

Still anotherobject of the invention is to provide a positive variable speed transmission unit, capable of transmitting reasonably unlimited horsepower, controlled by control means of a novel configuration having cam means which can be either manually or automatically operated for varying the speed of the transmission unit.

gear and/or a ring gear for producing a variable speed output. Also, the speed range maybe amplified further by means of other epicyclic or planetary gear trains, for example, so that the overall eli'ect is that the output is increased or reduced by the angular shifting of the planet gear or gears.

A still further object of the invention is to provide a variable speed transmission control means including planet gear means having controllably shiftable planet gears, the control means having epicyclic gear means statically and dynamically balanced along a common traverse plane. One of the advantages of the control weight is symsame transverse plane as the epicyclic gear means and not axially spaced relative thereto.

A still further object of the invention is to provide'a control mechanism which can be controlled very accurately through epic jCllC gear train means and minute movements of the control mechanism may be amplified or stepped down as desired so that a microscopiccontrol of the successive angular increments by which the planet gear or gears are shifted about the sun gear can be Still another object of the invention is to provide a positive varlable' speed and no-slip transmission which is constantly connected to the input and to the output shafts providing a smooth transition of speeds in either a positive or negative direction.

More particularly, it is an object of the invention to provide a variable speed transmission and the control means therefor which are substantially coaxial vand symmetrically disposed about the input and output shafts and where the variable speed transmission can be adapted to be connected to a planetary gear train in such a manner that a constant speed output can be maintained 'froma variable speed input, a variable speed obtained from a constant speed input, and/or a variable speed input can be varied as desired.

A further object of the invention is to provide a slip free variable speed transmissionhaving primary and output can be secondary outputs, the secondary output being variable and adapted to add to or subtract from the output speed of the primary.

Another object of the invention is to provide a slip free variable speed transmission having primary and secondary outputs, the secondary output being adapted to multiply by variable quantities the output speed of the primary.

The invention further resides in certain novel features of construction, combinations and arrangements of parts, and further objects and advantages of the invention will be apparent to those skilled in the art to which it pertains from the following'description of the present preferred embodiments thereof described with reference to the accompanying drawings, which form a part of the specifications, and wherein the same reference characters represent corresponding parts throughout the several views, and in which:

FIG. 1 is a fragmentary longitudinal sectional view along a longitudinal axis of a variable speed transmission embodying one form of the invention;

FIG. 2. is a sectional view along line 2-2 in FIG. 1; F FIG. 3 is a partially sectional view along line 3-3 in FIG. 4 is a fragmentary sectional view along line 4-4 in FIG. 1;

FIG. 5 is a fragmentary longitudinal sectional view of the invention embodied in an epicyclic gear train for providing a stepped down and/or stepped up constant speed output in one direction from a variable speed unidirectional input. More particularly, this embodiment is especially adapted for use in driving an alternator at a constant speed from a variable speed aircraft engine for creating a steady flow of electrical energy;

FIG. 6 is a fragmentray longitudinal sectional view of a variable speed transmission embodying another modification of the invention especially adapted to be used in connection with a constant speed power source for providing a smooth and positive variable speed output in either of two directions;

FIG. 7 is a diagrammatic and schematic transverse sectional view of the variable speed drive in FIG. 6;

FIG. 8 graphically illustrates the input torques of six ratchetable planet gears of FIG. 6 vs. cam plate and input shaft revolutions;

FIG. 9 is a fragmentary sectional view along line 9-9 in FIG. 3 and shows one of the spacers;

FIG. 10 is a view similar to FIG. 7 but showing a double eccentric cam drive for the six ratchetable planet gears; and

FIG. 11 is an enlarged view of a portion of FIG. 10.

It is to be understood that the invention is not limited to the details of construction and arrangements of parts shown in the drawings and hereinafter described in detail, and is capable of being otherwise embodied and of being practiced or carried out in various ways. Also, the phraseology or terminology employed herein is for the purpose of description and there is no intention to herein limit the invention beyond the requirements of the prior art.

The present invention provides several preferred embodiments of a variable speed transmission, which is almost entirely made up of a plurality or series of epicyclic or planetary gear trains, suitable for use in automotive vehicles as in FIGS. l-4; for driving alternators, FIG. 5, at a constant speed from a variable speed input in vehicles such as aircraft; and for providing a variable speed output, such as for a gun turret, from a constant speed input, FIG. 6. l l

A variable speed transmission embodying the inven tion, indicated generally by the reference numeral 10 in FIGS. 1 through 4, comprises an input shaft 11 in tandem with a coaxial output shaft 12. The variable speed transmission 10 further comprises a spider 13 splined on the outer end of the input shaft 11 and carrying a plurality of equiangularly spaced planet gears 14 journaled on axially extending parallel journal pins 15. Preferably, there are three planet gears 14 journaled between two integrally connected parallel, radially extending transverse flanges, which form spider 13. The input shaft 11, by way of the spider 13 and the planet gears 14, drives the output shaft 12 through an internally toothed ring gear or hub 16 splined to the output shaft 12. Both the input and output shafts 11 and 12 are journaled in a conventional manner in a multipart cylindrical housing, indicated generally by reference numeral 17.

In order to enable the transmission 10, comprising the primary output of planetary gear arrangement 13 and 14 to be a variable speed transmission, a second planetary or epicyclic gear arrangement forming a secondary output, is mounted concentrically about the input shaft 11 so as to add to or subtract from the primary output speed of the planet gears 14 in the instant embodiment.

The planetary gears 14 have their speed of rotation added to or subtracted from by a combined internallytoothed ring gear and axially movable brake actuating member 18 meshing with planet gears 19. The gears 19 are integrally connected to the planet gears 14 but are of reduced diameter relative thereto for changing the speed of the transmission 10. It will be understood that as the combined ring gear and brake member 18 drives the planet gears 14 in a direction the same as or opposite to the direction of the spider 13, the primary output at the ring gear 16 will be changed. Preferably the ring gear member 18, in the instant embodiment, is adapted to only subtract from the primary output of the transmission 10. For example, should the input shaft 11 have an input speed of +1, the output shaft 12 will have an output speed of -l to where 4 represents an output shaft speed of approximately a quarter of the input speed and in the same direction. Consequently, where the instant transmission is especially adapted for use in an automobile, the automobile can be driven, by disregarding the speed ratio of the ditferential, in a reverse direction at a speed of approximately one quarter the crankshaft speed or driven in a forward direction at approximately the crankshaft speed, which may be as high as 4000 RPM or more.

The ring gear member 18, FIG. 1, is driven from the input shaft 11 by means of a novel override and speed control arrangement 20 and a movable or adjustable cam and planet gear ratcheting or turning control arrangement 21 which can be either manually controlled or preferably automatically or remotely controlled through a servo mechanism.

In order to drive the ring gear member 18 at varying speeds, secondary drive planetary gear means, FIGS. 1, 3 and 4, preferably have six equiangularly spaced ratchetable, angularly shiftable planet gears 22. Preferably, the gears 22 have herringbone teeth and are each carried by an axially aligned shaft 23 journaled in a pair of parallel carrier plates 24. The plates 24 are held in spaced relationship by means of spacer bushing 24a each having a bolt 24b passing therethrough secured in the nut 24c, FIGS. 3 and 9. Each of the ratchetable planet gears 22 are drivingly connected to its respective shaft 23 by means of a unidirectional clutch, such as a Formsprag clutch, indicated generally by the reference numeral 25. The purpose of the unidirectional clutches 25 is to permit the planet gears 22 to be ratcheted in only one direction, a counterclockwise direction, in a manner to be described. Each clutch 25 permits the attached gear 22 to turn freely in a clockwise direction.

Each of the shiftable planetary gears 22 are adapted to mesh with an internally and herringbone toothed fixedring gear 25, forming a part of the housing 17, and is in driving connection with an axially movable or shiftable sun gear 27, also having herringbone teeth. The gear 27 Trade name of a product made in Detroit, Michigan.

. that as the cam plate 4% is is helically splined to a hub portion 180 of the ring gear and brake member 18. The sun gear 27 and the gear member 1% are respectively connected together by mating helical splines 28, 29 so that upon driving the sun gear 27 in one angular direction, the ring gear member 18 will tend to be forced in one of the two opposite axial directions. This will be described in detail later.

More particularly, the shiftable or ratchetable planetaries 22 of the change speed control portion of the variable speed transmission receive a velocity component from the input shaft ll by means of a sun-like spur gear 3t? splined to the shaft ll. A lone planet gear 31 is journaled about the shaft ll by means of a carrier wheel 32. The lone planetary gear 31 may, alternatively, be accompanied by several other planet gears in case a heavier construction is required. The planet gear 31 is rotatably journaled in the carrier wheel 32 by suitable anti-friction bearings 33. A stationary ring gear 34 fixed in the housing 27 by pin means 34a meshes with the planet gear 31 and is coaxial with the input shaft ll.

The carrier wheel 32 drives a second lone follower planet gear 35 which is journaled in the carrier wheel 32 by suitable anti-friction bearings 36. A coaxial sleevelike sun gear 37 is rotatabiy journaled upon the input shaft ll. The sleeve-like sun gear 37 has coaxial gear 38 of slightly greater pitch diameter integrally formed on its extreme right hand end, FIG. 1. The gear 38 is drivingly engaged with an internally toothed eccentric epicyclic gear-toothed portion 39 of a control cam disc or plate 40. The cam plate 40 has a closed circuit type of cam groove ll of an eccentric circular configuration adapted to drivingly engage a plurality of e'quiangularly.

spaced crank pins 52 having lever arms '43, preferably six in number, one for ratcheting and angularly shifting each of the planetary gears 22 relative to the axially movable gear 27 and about the fixed ring gear as. The pins 42 are each connected to the center of each clutch or ratchet shaft 23 by its crank arm 43 for rotating the shafts 23 and accordingly successively driving the planet gears 22 in a counterclockwise direction, FIGS. 3 and 4, but not in a clockwise direction due to the aforementioned unidirectional characteristics of the clutch 25. Since the ring gear 26 is fixed and the planet gears 22 are rotated in a counterclockwise direction, the sun gear 27 and the member 13 are driven in a clockwise direction, the same as the input shaft 11.

Also enmeshed with the gear 38 is a counterbalance comprised of an eccentric and internally toothed epicyclic ring gear 44 having a counterweight 45, of a selected mass, secured thereto. The counterbalance gear 44 is driven at the same speed 40 for statically and dynamically balancing the variable speed control arrangement Zil. A hub 46, which is fixed to the input shaft 11 by splines 47, is telescopically disposed in the cam plate 40 and retained therein by means of a snap ring 48. The gear 44 and counterweight 45 are turned within the hub 46 and the plate 40, which are and must be drivenat the same angular velocity.- The pins 42, extending from the cranks 43, each react against the cylindrical outer race of an anti-friction bearing 49 so rotated, the pins 42 will be oscillated outwardly and inwardly to crank the cranks 43 and ratchet the planet gears 22 in a counterclockwise direction. As the gears 22 are advanced, the carrier plates 24 will be carried by the shafts 23 about the shaft Ill. The periphery of each of the pins 42 tends to bear outwardly against the outer cylindrical sidewall of the cam groove ll due to the centrifugal forces generated and are thereby controlled by the contour of both the inner an douter sidewalls. However, preferably, in order to eliminate any counteracting forces, the inner sidewall of the groove 41 is comprised of the outer bearing race of the anti-friction bearing 49, the bearing 49 being secured within the groove 41.

One of the important features of the invention is that and direction as the cam plate The means used for varying the amount in which the cranks 43 are turned or pivoted per revolution of the shaft ll, is preferably embodied in the adjustable control arrangement 21 having a servo motor 50 driving a control pinion 51 which has external teeth enmeshed with a sec-- tor of gear teeth 52 in an angularly adjustable outer ring gear 53. The teeth 52, as best shown in FIG. 2, do not generally need to extend completely around the periphery of the movable, but normally relatively stationary, ring gear 53. Preferably, the sector of gear teeth 52 has an arc length of approximately degrees, depending upon the gear ratio between the control gear 51 and the cam plate ift. Ordinarily, the ring gear 53, enmeshed with the gear 51, remains stationary but by moving the ring gear 53 in either direction its internal teeth 54 advances the pinion 35 and the gears 37, 38. Visualizing that the input shaft 11 is stationary, then the only movement given the gear 38 is that caused by the servo 50. At the same time, the relative position of the cam plate 40, driven by the gear 38;, is changed by an angle relative to the hub 46. Angle q) is fully explained in the description of FIG. 6 and is illustrated in FIGS. 10 and 11. Since the eccentric outer peripheral surface 46a of the hub 4e and the groove 41 of the cam plate 43 are eccentrio to the shaft ll. by a maximum distance e, the eccentricity e of the circular groove 41 can be varied between zero and some maximum. When the eccentricity e is zero, the angle p is preferably zero and the groove 41 has no effective throw. As a result, the crank arms 43 are not moved through an angle. The movement of the crank arms 43 is expressed as an angle 8 and the effective angular movement of the planet gears 22 per revolution of the shaft ll can therefore be expressed as where 6 is the instantaneous input angle of the shaft '11. Since, in the instant embodiment, the maximum speed is the speed of the input shaft although in an opposite direction, it is preferred that at maximum output speed the eccentricity e be zero. Therefore, when the output speed is reduced, the eccentricity :2 Will be increased and at the reverse speed of the eccentricity e Will be a maximum.

I The purpose of the override speed control arrangement 2% is to assure that the cam plate 41} will have the same angular velocity as the input shaft 11 so that the relative position of the hub as relative to the cam disc 40 or angle will always remain constant and therefore the eccentricity e will remain constant once the adjustment of angle has been effected from servo 5t} through the pinion 5f, the ring gear 53 and the follower planet gear 35 and the gears 37, 38 to the cam plate 40. If a 1:1 ratio were not assured, it would result in the adjustment by the control arrangement 21 being nullified or otherwise rendered ineffective and result in an uncontrolled constantly changing speed ratio through the planet gears 22 to the ring gear 27, out through themember 18, the pinion gears 14, the ring gearor hub 16, and the output shaft 12. l

One of the problems encountered in starting and transferring initial torque from the input shaft 11 tothe output shaft 12 in the variable speed transmisson 10 resultsin the input torque or movement through the shaft 11 and the spider 13 to the pinion gears 14 tending to be transferred back and tailing out through the secondary drive means, comprising the member 18 and the planets .22, and resulting in insuflicient net torque output to drive the output shaft 12. This is due to the static inertia and load on the output shaft 12 tending to prevent any torque being transferred therethrough. Hence, the output of the input shaft 11 is rendered ineffective since its output would be tailed off, so to speak, through the planets 22. Therefore, a braking arrangement is relied upon to prevent the member 18 from driving the gears 27 and 22 but yet permit the member 18 to be driven by the gears 22 and 27. The braking arrangement includes a stack of brake rings or discs 61 and 62.

The brake rings 61 are keyed to the housing 17 and the brake rings 62, alternately disposed between the rings 61, are keyed to the ring gear and brake member 13. The helical splines 28, 29 extend in a clockwise direction so that any load applied to the ring gear and brake member 18 from the axially movable sun gear 27 results in an axial shifting to the right of the member 18, FIG. 1, and the frictional braking engagement of the brake rings 61, 62. As will now become apparent, the reason for the gears 22, 26 and 27 having continuous herringbone teeth, FIG. 4, is to prevent the axial shifting thereof relative to the member 18. Although it is understood that herringbone teeth are preferred, other types of teeth or equivalent means can be provided or substituted therefor. Also, the member 18 is journaled on the input shaft 11 by suitable anti-friction means, comprising roller bearings 64 and axially spaced apart cylindrical outer races 65, capable of permitting the axial shifting of the member 18.

When the input shaft 11 is turned in the clockwise direction, the output shaft 12 is rotated in the clockwise direction when the eccentricity e is a maximum and in a counterclockwise direction when the eccentricity e is Zero, as pointed out. Accordingly, the planet gears 22 are driven in a counterclockwise, FIG. 3, direction and the sun gear is driven in a clockwise direction. The reaction of the hub 18a of the member 18 is then in a left hand direction, as seen in FIG. 1, and the brake rings 61 and 62 are separated. This permits the driving torque to be transferred from the member 18 to the planet teeth 19 and the planet gears 14. In this manner a proper transfer of driving torque from the input shaft 11 to the output shaft 12 will always be assured without movement being transferred to the secondary via the member 18.

Alternatively and aside from the embodiment described, should it be desired for the secondary to add to the speed of the primary, the member 18 can be driven faster in a clockwise direction, the same direction in which the primary drives the planet gears 14, the counterclockwise rotation of the planet gears 14 will be slowed down and perhaps reversed in direction so that the speed of the output shaft 12 is increased over the speed of the input shaft 11.

Referring to FIG. 5, the invention is shown embodied in a variable speed transmission 79 suitable for driving an alternator off of the output shaft 12 from a variable speed power source, such as an aircraft engine drivingly connected to the input shaft 11. Only the part of the variable speed transmission 10 which has been modified is shown in FIG. 5.

Preferably, the transmission of FIG. has a speed range of from two-thirds to twice the speed of the input shaft 11 and in the same clockwise direction at the output shaft 12. This is accomplished by multiplying the angular velocity of a spider-like driving member 72 generally comparable to the brake and ring gear member 18 in FIGS. 14 by its directly preferably driving three planetary output gears 66, from the planet gears 22, in a coaxial circular path about the shafts 11 and 12. The output shaft 12 has a power pick-off sun gear 67 on its juxtaposed end that meshes with and is driven by the output gears 66.

There is no adding or substracting of the output of the shiftable planetary gears 22 as in the embodiment of FIGS. 1-4 and FIG. 6, which will be described hereinafter, for the reason that power is transferred through the secondary override and speed control arrangement 26', FIGS. 1-4, and not directly to the output shaft by 8 way of primary gearing such as the spider 13 and planetary gears 14 of FIGS. 14.

The present embodiment of FIG. 5 does not require the use of the herringbone type of gear teeth in the planetaries 22 and the member 72. This is because there is no dual input of power from the primary and the secondary drive, and the resulting tailing-off phenomena cannot arise in the secondary.

More particularly, the planetaries 22 are connected to the planet shafts 23, preferably by the unidirectional ratchet-like clutches 25 as in the preceding embodiment, but the shafts 23 are not moved in a circular path about the input shaft 11 since they are journaled in the housing 17. A sun gear 68, integrally connected to one end of the member 72, is driven by the planet gears 22. in the instant embodiment, each of the planet gears 22 are rotated about their respective shafts 23. Each of the shafts 23 are journaled at the outer ends thereof by means of ball bearings 71 rigidly secured in the housing 17 by means of parallel, transverse, and annular flanges 73, 74 integrally connected thereto.

The output end of the input shaft 11 is coaxially journaled within the adjoining end of the output shaft 12 by means of a tandem or twin needle bearing assembly 75. The member 72 is journaled on the reduced end portions of the input shaft 11 and the outer race of bearing assembly 75 by means of anti-friction roller bearings 76 and needle bearings 77, respectively. Both shafts 1i and 12 are journaled in the housing 17, such as with conventional anti-friction bearing assembly 73, in a manner well understood in the art.

An internally-toothed, stationary ring gear 30 is fixed within the housing 17 and adapted to have its teeth mesh with the planet gears 66. However, where the stationary outer ring gear 26 is shown in FIGS. 1-4, no similar ring is provided in FIG. 5 about the planet gears 22. The effect of the omission of the outer ring gear, such as the ring gear 26, for the planet gears 22 is that the latter must then be ratcheted twice the angular increment than that which would ordinarily be required. The gears 22 in FIG. 5 are ratcheted in a counterclockwise direction while both the input and output shafts 11, 12 are driven in a clockwise direction. Restated, the provision of the internally-toothed ring gear about the planet gears 22 has been found to double the variable speed output caused by the shifting of the planet gear 22 a given angular increment and reduces the required range of the eccentricity e for a given speed range. As is now apparent, the provision of the internally toothed ring gear for the planet gears 22 can be made optional depending upon the wishes of the user.

it will also be apparent that when the crank arms 43, FIGS. 1-4, are not moved through an angle 5, the angular movement of the planet gears 22 is zero since the term is zero. Consequently, in the present embodiment, FIG. 5, the output of the transmission is zero. However, since the output is desired to be two-thirds to twice that of the input, the crank arms 43 will always be moved through some angle with the minimum angle being designed to give the minimum output speed.

Referring to FIG. 6, the invention is shown embodied in a variable speed and slip-free transmission suitable for use in connection with a gun turret, the gun turret being driven from the output or driving pinion 79 from the input shaft 11 which is connected to a constant speed drive. FIG. 6, like FIG. 5, contains only that part of the transmission 10 which is materially different from that shown in FIGS. 1-4.

Preferably, for purposes including compactness, the primary output comprises an eccentric circular cam 11a located adjacent the outer end of the input shaft 11 for oscillating or driving a ring-like sun or follower gear 80,

which operates as an output gear drive for the output pinion 79. The output gear 86 is disposed about the cam 11a by means of an anti-friction bearing assembly 81. The output gear St} has helical external teeth meshing with the helical internal teeth 82 of a secondary drive gear 83, which also has helical external teeth 84. The gear 3i) is rotated by an increment of two teeth, for example, for every revolution of the input shaft 11, the number of teeth of the follower or output gear Sil being less in number than the number of teeth 82 of the secondary drive gear 83. By considering the secondary drive gear 83* as fixed, the following equation expresses the number of turns N of the output pinion 79 per turn of the input shaft ll:

T82 7: A 1 T80 where represents the ratio of the number of teeth 82 of the secondary driving gear 13 to the number of teeth of the primary follower gear 80, FiGS. 6 and 7. The follower gear 8i) drives the output pinion 79 through a plurality of parallel and equi-angularly spaced pins 85 fixed to the gear 86 and extending in an axial direction to the right, as seen in FIG. 6. The pins 85 extend into complementary radial openings or slots, formed in an annular drive plate 86 fixed to the output pinion 79. The pinion 79 is rotatably journaled on a coaxial supporting shaft 88 by means of an anti-friction needle bearing assembly 9i), the journal shaft 88 being coaxial with the axis of rotation of the tandem input shaft 11. The juxtaposed end of the input shaft 11 is journaled within the pinion 79 by means of a suitable anti-friction bearing assembly 91. Both the pinion 79 and the input shaft are rotatably mounted in the housing assembly, indicated generally by the reference numeral 17, by means of anti-friction bearings, such as bearing assembly 9'2.

Since the input is clockwise in FIGS. 6 and 7, the direction of rotation of the output pinion 79 is counterclockwise, but the output speed is only a fraction of the input speed of the shaft 11, as pointed out, when the secondary drive gear 83 is fixed. But by driving the secondary drive gear 83 in a clockwise direction, the follower gear fill can be slowed down, stopped, and driven in a reverse or clockwise direction. In the instant embodiment, for example, the output speed of the pinion 79 preferably varies from to 3 of the input speed of the shaft 11.

-By cranking the shiftable or ratchetable planet gears 22 in a counterclockwise direction about the shafts 23, the secondary driving gear 83 can be driven in a clockwise direction.

The planet gears 22 are driven by means of the one-way or unidirectional clutches 25 as the shafts 23 are rotated. The shafts 23 are mounted in the anti-friction bearing assemblies 93 mounted at either end thereof in the stationary parallel annular support flanges 9a, which are fixed to the inner wall of the housing 17. Preferably, the teeth of the planet gears 22 and the teeth 84 of the gear 33 are straight so that gear 33 can be axially shifted to the left for compressing a stack of annular brake rings or discs 95 and 96. T he discs 95 and 96 are alternately keyed to the gear 83 and the left-hand support plate 94. The meshing helical teeth of the secondary drive gear 83 and the follower gear 80 are twisted in a counterclockwise direction so that the primary drive from the follower gear cannot be transferred through the secondary drive gear 83 without causing the gear 83 to shift to the left, FIG. 6, and cause the brake discs 95 and 96 to be compressed and thereby brake the gear A circular anti-friction bearing race 7 is carried by the right hand flange 94 for supporting a plurality of equiangularly spaced balls 98 between the flange 94 and the gear 83. Normally, the gear 83 bears against the balls @8, which bear against the race 97 when the secondary is transmitting torque.

By shifting or cranking each crank arm 43 through an angle a with the eccentricity of the driving cam plate 40 being represented by angle qt, as in the preceding embodiments, then the incremental movement of each of the six planet gears 22 is represented by the term and the output S of the secondary driving gear 33 per revolution of the input shaft 11 may be written as By combining like terms,

Then by substituting the equivalent of 8, Equation 2, into Equation 4,

Since FIG. 6 in its preferred form, has an output range of to of the input, then when the output of the secondary S is zero, the speed N of the pinion 79 will be in a negative or counterclockwise direction, but as the value of S increases, the output N will approach zero; and if the value of S is further increased, the value of N will become positive and the pinion '79 will be driven in a clockwise direction, as viewed from the left in FIG. 6. v

In the embodiment of FIGS. 1 -4, when 2 is a maxi mum, the output is a minimum or 4 and when e is zero the output is -'1 or the same as that of the input shaft 11 although in an opposite direction, as pointed out hereinbefore.

Although it is always preferable to have the eccentricity e zero at maximum output speeds, this is not possible in the embodiment of FIG. 5 where the minimum value of the eccentricity e provides an output of of the input shaft speed and the maximum value of e provides an output speed of +2.

As in the preceding embodiments of FIGS. 1 through 4 and FIG. 5, the oscillatable cam plate 40 must be driven at the speed of the input shaft 11 in order for the cocentricity e to remain constant. The servo 59, upon being energized, drives the gear 39 and causes'it to be turned relative to the hub 46 by an angle as, FIGS. 10 and 11, which may vary from 0 to The value of e is maximum when as is 189.

Referring particularly to FIGS. 10 and ll, it is apparent that the value of e is proportional to the angle (p, p being the angle through which the gear 39 or' the cam plate 4% has been adjusted relative to the hub as. In the instant embodiment, if the eccentricity e is zero, the output of the secondary is zero. Alternatively, the maximum value of the eccentricitye is obtained by ro- 1 l tating the plate 45 through 180 relative to the hub 46. For example:

(6) e 261 sin or (7) e=e \/2(lc0s 11 where e, is the radius of the circle 11% because s will always extend from the center of the input shaft 11 to a point on the periphery of the circle lit But where (8) e max=2e then (9) e=e max sin /2 It is understood from the foregoing and by referring to FIG. 10 that any point on the cam plate 40 follows a circular path having a radius e at any given angie and because of this motion the crank arm 43 is oscillated such that:

sin =e/R cos 9 8=sirr [e/R cos 0] 6=the instantaneous angle of the input shaft 11 and is not to be confused with the adjusted angle e of the cam plate 4% relative to the hub :5 by the servo 5d.

6=the instantaneous angle of the crank arm 43 or the planet gears 22.

R=radius of the crank arm 43.

e=eccentricity of the driving cam plate it being necessary to determine the angular velocity of the planet gears 22 to determine the output of the secondary S.

Referring to FIG. 8, the intermittent torque drive of each of the planet gears 22a, b, c, d, e, f is illustrated as a sinusoidal curve having a half wave length of 180. The average torque output of each planet gear 22- is illustrated by a dotted horizontal line 102 in FIG. 8 and is slightly less than the peak or maximum torque output.

As the crank arms 43 of the six planet gears 22a, [1, c, d, e, f, FiGS. 7 and 10, are successively actuated by the oscillating cam plate as, the maximum torque transmitted by each gear 2241-1 is spaced 60 or A5 of a revolution of the cam plate 48 and input shaft 11 apart. However, the angular acceleration of each crank arm 43 generally approaches uniform motion. When the angular acceleration of each crank arm 43 is zero, the angular velocity of each crank arm 43 is uniform.

It is apparent then that a relative uniform and smooth transmission of power or torque is transmitted to the secondary output. However, from FIG. 8 it is seen that a large number of planet gears 22 is desirable but the number must be limited due to the spatial limitations encountered and the gear ratio requirements.

While several specific embodiments of the invention have been shown and described, it is understood that the same are susceptible of many changes and modifications,

as known to one skilled in the art, and it is intended to cover such changes and modifications coming within .the scope of the appended claims.

What is claimed is:

1. In a variable speed transmission, an input shaft, an output shaft, primary spider means connected to said input shaft and carrying primary planet gear means, brake ring gear means meshing with said primary planet gear means, output ring gear means drivingly connected to said output shaft and meshing with said primary planet gear means, a fixed ring gear means, secondary planet gear means drivingly connected between said brake ring gear means and said fixed ring gear means, secondary spider means coupled to said secondary planet gear means by a ratchet for rotation in only one direction, cam plate means coaxial with said input shaft and having a circular groove eccentrically disposed therein, crank means connected to said ratchet and disposed in said groove for rotating said secondary planet gear means, and means for positioning said cam plate means thereby changing throw of said crank means and the angle through which said secondary planet gear means are driven for each revolution of said input shaft.

2. In a variable speed transmission, a rotatable input shaft, a rotatable output shaft, first gear means drivingly connected between said input and output shafts, second gear means drivingly connected to said first gear means for varying the speed of said output shaft relative to said input shaft, shaft means drivingly connected to said second gear means and including a clutch for providing driving motion in only one direction at the output thereof, rotatable cam means having a continuous eccentric surface operatively connected to said shaft means for producing driving motion from said second gear means in said one direction, third gear means drivingly connected between said input shaft and said cam means for providing simultaneous rotation, and control means operatively connected to said third gear means for varying the angular position in rotation between said input shaft and said cam means; whereby the relative angular velocity of said input and output shafts may be varied.

3. In a variable speed transmission, an input shaft, an output shaft coaxialiy positioned with said input shaft, a first carrier coaxially connected to said input shaft for rotation therewith and rotatably supporting a first plurality of planet gears, a first ring gear means coaxially connected to said output shaft for rotation therewith having internal teeth meshing with said first plurality of planet gears, a second ring gear means coaxially disposed about said shafts for rotation relative thereto having internal and external teeth, pinion gears coaxially connected respectively to each of said first plurality of planet gears for rotation therewith and meshing with the internal teeth of said second ring gear means, a cam coaxially connected to said input shaft for rotation therewith, a second carrier coaxially disposed about said shaft for rotation relative thereto rotatably supporting a second plurality of planet gears meshing with the external teeth of said second ring gear means, clutch means operatively disposed between said second carrier and each of said second plurality of planet gears for restraining rotation of the latter in one direction relative to said second carrier, a third ring gear means coaxially disposed about said shafts and fixed against rotation having internal teeth meshing with said second plurality of planet gears, a plurality of cranks respectively fixed at one end of each to said clutch and slidably engaged to said cam at the other end of each, and means for selectively positioning said cam for changing the eccentricity of said cam relative to said input shaft and thereby changing the throw of said cranks; whereby the speed of said output shaft is equal to the algebraic sum of the speed of said input shaft and a factorial amount of any selected position of said cam.

4. In a variable speed transmission as set forth in claim 1, wherein said positioning means include hub means fixed to said input shaft, and said cam plate means is slidably disposed about said hub means in such a manner as to be turnable relative thereto.

5. In a variable speed transmission as set forth in claim 4, wherein said hub means has a circular outer periphery,

13 said cam plate means has a circular inner periphery of substantially the same diameter, the inner periphery of said cam plate means being slidably disposed about said outer periphery of said hub means, and both said inner and outer peripheries having centers eccentric to said input 5 shaft.

References Cited in the file of this patent UNITED STATES PATENTS 928,486 Williams July 20, 1909 14 Wodal et a1 Sept. 13, 1949 Cutler July24, 1951 Malrnsten Jan. 29, 1952 FOREIGN PATENTS Great Britain May 25, 1905 Denmark Sept. 7, 1914 Canada Dec. 11, 1930 Italy Mar. 30, 1951 Germany June 26, 1952 France Apr. 22, 1955 

